Taiwanese company KingRex has established
itself as of late as a purveyor of innovative, affordable, and highly
regarded components in a variety of categories. A quick look at their
website and you will see amplifiers, headphone amps, preamps, speakers,
cables, DACs, USB converters, and power supplies. You can actually
assemble a complete audio system with KingRex products, from soup to
nuts. KingRex is also an OEM manufacturer, supplying many parts and
modules to other manufacturers.

Their UD384 portable USB DAC has been quite
a hit, with many positive pro and amateur reviews globally. I was given
the opportunity to take a listen to their uArt Y USB cable and the
UPower battery power supply. The products come beautifully packaged,
and with well written product literature. The uArt cable is $599,
and the UPower is $199 at time of publication.

As the name suggests, the cable has separate
power and data leads. It is extremely well built, and quite attractive
with red aluminum connector shells, which have gold plated copper alloy
contacts, and a nice textured red outer sheath. KingRex also says the
cable is cryogenically treated. The conductors are reportedly silver
plated oxygen free copper sourced from WireWorld. There also seems to be
some sort of resonance control purpose to the middle shell from which
two of the connector leads emerge.

As I understand it, the best use of the
UPower would be with a hub powered USB device, either a converter, or
stand alone DAC. However, I have been told by a few computer audiophiles
far more knowledgeable than me, that
anything you use with the KingRex cable should sound better if you use
power from the battery, even in the case where the connected device has
its own power and does not rely on bus power. This is because it will
break the common ground with the source, and only get data from the
computer. All USB conductor lines are subject to contamination from the
computer (even the data line +/-), so the ground and V+ will come from
the quiet battery and only the data line +/- has the potential for some
infection from the computer. This will all be system dependent.

Some devices
that are not bus powered still require as part of their controller
chip's USB handshake initialization process the presence of +/- 5 V and
a ground reference or they won't work. So it's entirely possible that
some devices won't operate if connecting only the data end of the
KingRex dual head cable, it might require both heads to be connected; at
which point the battery will outperform the computer due to a quieter
more tightly regulated voltage, and clean low impedance ground
reference.

Following the user manual, I made very sure
the toggle switch on the UPower was pointing towards, "charge", and
plugged in the supplied wall-wart power supply. When fully charged, I
connected one end of the Y cable labeled for data into both the source
and DAC, and the other end with the battery symbol in to the UPower.

I first used the KingRex cable and power
supply with two Marantz products, the superb NA-11S1 file player,
streamer, and PCM/DSD DAC, and the SA-114S1 SACD player & PCM/DSD DAC. I also used it with the fantastic Simaudio Neo 380D DAC. My findings
below are blended from my impressions with all three. I did not have
any bus powered devices on hand. So this was going to be a test of the
above theory that even non bus powered devices would benefit.

Other moving parts included a Windows 7
laptop with JRiver 19, with FLAC files on an attached external 1 TB
drive. I had files of every resolution known to man, from 44.1kHz to DSD.
I started with Redbook, CD quality rips and moved on from there. I
initially used my DH Labs USB cable, my usual reference, an excellent
overall performer at roughly around $100 for a meter.

FIrst impressions when switching over to the
KingRex combo? A bit stunned at the absolutely quiet backgrounds, I mean
black as black can be. Soundstaging was more precise and
individual instrumental images seemed to float free of the speakers. I
was thinking to myself, "possible game changer". If the UPower could
make this much of a difference when using a computer with a
device equipped with a high quality linear power supply, then imagine
the difference when using a device that requires the computer for power.

As I progressed through various musical
reference material I was really taken aback at how the KingRex cable and
UPower were allowing me to differentiate between different masterings of
the same material, like the Grateful Dead HDCDs, and the recent 192kHz,
24-bit remasters. The high resolution remasters from HDTracks were
superior, although the HDCDs held their own. DSD sounded absolutely
incredible via the Marantz and KingRex rig. Beyond description really. I
donít have a ton of DSD files, but the small amount I have are stellar.
I especially recommend the High Definition Tape Transfers DSD files.
They are pretty remarkable.

I also highly recommend singer songwriter
David
Elias, one of the only pop musicians to embrace DSD as a
native recording format. He offers a number of free downloads on the
Oppo website, where you can directly compare 44.1, 88.2, and DSD. Quite
eye opening. The music is great, and so is the sound. The
Marantz units and the KingRex duo made me a believer in its ability to
resolve very fine detail, and retain the full body and tone of voices
and acoustic instruments.

Having spent a several months with the
KingRex uArt Y USB cable and UPower I have to say the pair is very, very
easy to recommend, even for non hub powered devices. It seems they left
no stone unturned in regards to quality. Build is beyond reproach, and
the cable is attractive. The UPower is sturdy. By the way, I never ran
out of juice on the uPower during my listening sessions, which averaged
about two hours. I did make sure to charge the unit after two or so
sessions. Your mileage may vary.

Overall I really enjoyed using the KingRex
uArt Y USB dual lead cable and the UPower module. They improved the
sound, in my case, with non hub powered devices, probably due to reasons
discussed above. There are similar options on the market, but for far
more money. If you use a computer as a digital source, you owe it to
yourself to take a listen to both these products. Well done KingRex.
Andre Marc